The invention generally relates to thermal wave imaging, and more particularly relates to thermal wave imaging with nanoparticles.
Atherosclerosis is a common human ailment arising from the deposition of fatty-like substances, referred to as atheromas or plaques, on the walls of blood vessels. While some plaques are relatively stable, others are vulnerable to rupture and release their contents into the bloodstream, causing a blood clot to form. Heart attacks and other acute cardiovascular events usually result from the rupture of high-risk, vulnerable plaques in coronary arteries. Vulnerable plaques are believed to have three major characteristics—a deposit of lipids, a thin cap of fibrous material covering the lipid pool, and infiltration of the immune cells called macrophages. Such deposits occur in both the peripheral blood vessels, and the coronary vessels. When deposits accumulate in localized regions of a blood vessel, stenosis, or narrowing of the vascular channel occurs. Blood flow is restricted and the person's health is at serious risk. Early detection and characterization of arterial plaque can identify patients who are unaware that they are at risk of suffering a myocardial infarction or other cardiovascular events such as stroke.
Recently, temperature differences correlated positively with cell macrophage density in atherosclerotic plaques. Thermal heterogeneity is increased in unstable atherosclerotic plaques compared to stable plaques, roughly by 0.3° C. from macrophage activity and the inflammatory response thereof. However, recent mechanisms to determine the thermal changes in the plaques are complicated by the cooling effect of blood flow causing a high signal-to-noise ration in the thermal imaging techniques. Such complications do not result in precise location of unstable atherosclerotic plaques.
The present invention attempts to overcome the shortcomings of the cooling effect of blood flow by administering a plurality of metallic nanoparticles to localize in macrophages, heating such nanoparticles with a pulsed laser, and imaging the temperature affects in the plaque with a thermal sensor.